Three stage filter



FIG. 1 is a top perspective view of a three stage filter according to my new design;

FIG. 2 is a bottom perspective view;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a left side elevation view thereof; and,

FIG. 8 is a right-side view thereof.

The broken lines and areas within depict portions of the three stage filter that form no part of the claimed design. 

CLAIM I claim the ornamental design for a three stage filter, as shown and described. 